Instructables

Make a Spade Bit of any size out of scrap

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I needed a 40mm wide hole. The shop didn't have a 40mm bit. Necessity is mother of invention so I invented my own hole maker. Here's how I did it.

Of course I could have bought an adjustable bit for the princely sum of 5000 yen but I only needed two holes. Again, necessity is the mother of invention.

One fine day I was building a foot powered lathe inspired by Don Weber. I couldn't find any cheek block bearings anywhere around south Yokohama so I caved and bought some big sealed roller bearings (similar to but larger than those in rollerblades or skateboard wheels). This presented a new problem: I needed to mount the bearings in wood. So why not drill a hole the same size as the bearings? Because I couldn't find an appropriate bit, that's why. Ah yes, the plot sickens.

So naturally I found my solution where I find all my answers: a dead bicycle; the frame of a bike to be precise.

Danger, warning, achtung! Danger, warning, achtung! Danger, warning, achtung!
Danger, warning, achtung! Danger, warning, achtung! Danger, warning, achtung!

This tool is risky. It has a chance of shooting a sharpened hunk of metal at high velocity in a random direction and hurting someone badly. Please be very careful if you use this!

Danger, warning, achtung! Danger, warning, achtung! Danger, warning, achtung!
Danger, warning, achtung! Danger, warning, achtung! Danger, warning, achtung!
 
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Step 1: Parts and tools

Picture of Parts and tools
Ingredients:
-One thin-walled steel pipe ~3 inches long x an arbitrary width (mine was from a bike frame)
-a screwdriver bit with a hexagonal butt end (this is really just an adapter to mount the bit in a drill).
-two short machine screws and nuts. I used 1/4 inch screws.
-and the secret ingredient: love.

Tools:
-drill
-drill bit the same size as your two machine screws.
-bench grinder (or a file and patience).
-hack saw
-a big flat screwdriver
-vice
-hammer
-measuring tool (vernier calipers recommended)
-love

pfred22 years ago
You have mad skills! I love bike parts for projects too.
snotty (author)  pfred22 years ago
Cheers!
So, is this dangerous ? :)

Nice instructable, thanks for sharing!
snotty (author)  scraptopower3 years ago
Glad you like it :)

I think it's dangerous.

So did my neighbor.

But I did it anyway.
Good! Without risk takers, we'd have nothing! :)
Nice work. Very clever.